Starting device for arc-lamps.



G. M. LITTLE. STARTING DEVICE FOR ARC LAMPS Patented July 19, 1910.

APPLICATION FILED SEPT.3,1907.

WITNESSES:

A'TTORNEY UNITED STAElEtl lite/Edith o it "w r n-"av 1 T GEORGE M.LITTLE, OF PITTSBURG, PENNSYLVANIA, ASSIG'NOR TO XVES'IINGHOUSE ELECTRIC& MANUFACTURING COMPANY, A CORPORATION OF PENNSYLVANIA.

STARTING DEVICE FOR ARC-LAMPS.

Specification of Letters Patent.

Patented July 19, 1910,

Application filed September 3, 1907. Serial No. 391,239.

To all whom it may concern:

Be it known that I, GEORGE M. LITTLE, a citizen of the United States,and a resident of Pittsburg, in the county of Allegheny and State ofPennsylvania, have invented new and useful Improvement in StartingDevices for Arc-Lamps, of which the following is a specification.

My invention relates to arc lamps and particularly to lamps in whichinsulating fumes or bodies of slag sometimes deposit or form upon theelectrode and interfere with ready starting of the arc.

The object of my invention is to provide simple, reliable andinexpensive means for causing movement of the electrodes of arc lampsinto and out of engagement for the purpose of removing the slag andfumes that deposit thereon. I

Are lamps are now frequently provided with electrodes containingmaterials that render the same less readily consumable than ordinarycarbons and that also insure the production of arcs of greaterluminosity than those produced by ordinary carbons, one suitablecomposition for securing these results comprising the magnetic oxid ofii-oi'1'(l e,,() as the prcdominent constituent, which givesconductivity to the electrodes both when hot and when cold, chromiumoxid 10,), which, by reason of its very high fusing point, assists inpreventing rapid consumption ot the electrodes and flickering of thearc, and titanium oXid (TiO or some other compound of titanium, whichimparts color and brilliancy to the arc and also assists in prolongingthe life of the electrode. In the use of electrodes having the abovespecified composition, bodies of insulating slag, composed largely ofnon-conducting oxids, sometimes form uponthem and thus prevent goodelectrical contact when they are brought into engagement for the purposeof starting the arc.

In order to insure suiiiciently good electrical contact between theelectrodes to permit of ready starting of the arc, it has been proposedto remove the slag from the ends of the electrodes by causing rapidmovement thereof into and out of engagement until the arc isestablished. The means that have herctotore been provided for eii'ectingthis result have been complicated and expensive and have embodied partsrequiring accurate adjustment, such, for instance, as dash pots or otherretarding devices, thus increasing the first cost as well as the cost ofmaintenance.

The present invention provides a device of extreme simplicity thatrequires no adjustment or attention after having been installed in alamp. and is exceptionally eti ectivc and reliable in operation.

Figure 1, of the accompanying drawings, is a perspective view of aportion of a lamp that embodies my invention. Fig. 2 is a view,partially in side elevation and partially in section, of certain of the.parts shown in Fig. 1, and Fig. 3 is a diagrammatic view of the circuitsof a lamp embodying my invention.

Electrodes 1 and 2 of an arc lamp, either or both of which may becomposed of the oXids above specified, or other suitable materials, aremaintained normally out of engagement by means of a ring clutch 3 thatengages the electrode 1. The clutch 3 is pivoted to the-lower end of arod 4: that is attached at its upper end to a U-shaped elec tro-magnetcore'5 having a winding 6, the said parts being normally maintained inthe position shown,.by means of a spring 7. One terminal of the winding6 is connected to a switch member 8 that cooperates with another member9, and is actuated by an clectro-magnet having a winding 10, therespective terminals of which are connected to the electrodes 1 and 2.The switch member 9 is connected to the terniinal 12 of the lamp, and isactuated by an electromagnet having a winding 11 that is included in theseries with electrodes 1 and 2 between terminals 1.2 and 13 of the lamp.

Included in series with the winding 6 is a resistance 14 and a conductoror heating coil 15 of a switch device 16 that governs a. shunt to thewinding 6, the resistance 1a and the winding 15. 'The switch device 16comprises normallyseparated stationary and movable contact terminals 17and 17, the terminal 1?? being mounted upon the upper free extremity ofan actuating arm 18, the lower end of which is secured to a stationaryplate or bracket 19. The arm 18 is coniposed of two strips or bodies 20and 21 formed of materials, such, for example, as copper and iron, whichhave different coefficients of expansion when subjected to variations intemperature, and is subjected to varying degrees of temperature by theconductor or winding 15 which is here shown as surrounding it butinsulated from it The conductor or winding 15 may, of course, bedisposed or arranged in any other suitable manner with respect to thearm 18 so that, when current traverses said winding, the heat producedtherein will be transferred to the arm. The arm 18 is provided withlaterally projecting armature 22 that extends into the field produced bythe electro-magnct winding 6.

When current is first supplied to the lamp, it traverses a circuitincluding the winding 15, the resistance 14, electro-magnet winding 6and switch terminals 8 and 9that are normally in engagement. The magnetwinding 6, being thus energized, causes the magnet core 5 to be drawndownwardly against the tension of the spring 7, and the electrode 1 isthereupon lowered into engagement with .the electrode 2. If a goodelectrical contact is established between the electrodes a circuit iscompleted from the lamp terminal 13 by way of magnet winding 11 andelectrodes 2 and 1 to the terminal 12, and the switch terminal 9 will beraised out of engagement with the terminal 8 by the magnet winding 11.Separation of the switch members 8 and 9 interrupts the circuit of themagnet winding 6, and the. magnet core 5, together with the electrode 1,are raised by means of the spring 7, an arc being thereupon establishedbetween the electrodes 1 and 2. If, when the electrodes 1 and 2 arebrought into engagement,'only an imperfect electrical contact is formedbetween them, the magnet winding 11 will not become suiiicientlyenergized to eifect separation of the switch terminals 8 and 9, and thecircuit including devices'15, 14, 6, 8,-and 9 remains established.Continued passage of current through the coil 15 raises the temperaturethereof, and in turn the temperature of the strips 20 and 21, which eX-pand unequally and cause the terminal 17 to move toward and intoengagement with the stationary terminal 17 in opposition to the force ofattraction exerted by the magnet winding 6 upon the armature 22. Whenthe terminals 17 and 17 engage each other, the electro-magnet winding 6is shunted and the armature 22 is released, so that the terminal 17 ispressed firmly into engagement with the terminal 17. The electrode 1 isalso raised out of engagement with the and 17 come into engagement andthe said coil, as well as the strips 20 and 21, are per causing theterminals 17 and 17 to separate more'widely. Thus, the cooperation ofthe armature 22 and the magnet winding 6 serves to cause firm engagementand quick separation of the terminals 17 and 17 and to prevent vibrationof the arm 18.

Energization of the magnet winding 6 also causes the electrode 1 toagain engage the electrode 2. The electrode 1 will thus be subjected toa continuous reciprocating movement until the slag or other insulatingobstruction upon the electrodes is removed and a suiiiciently goodelectrical contact is established between the electrodes to permit readystarting of the are.

I claim as my invention:

1. In an arc lamp, the combination with electrodes, and means,comprising an electro-magnet winding, for moving the same into and outof engagement, of a switch for governing a shunt to the electro-magnetwinding, and actuating means for the switch comprising rigidly connectedbodies formed of materials having d-iiierent coefficients of expansion,a conductor located adjacent to:

the said bodies and connected in series with; the electro-magnetwinding, and an arma-' t-ure carried by the-said switch and subject tothe influence of said electro-magnet winding.

2. In an arc lamp, the combination with electrodes, and means,comprising an electro-magnet winding, for moving the same into and outof engagement, of a switch for governing a shunt to the electro-magnetwinding, a thermostatic actuating device for the switch having aconductor in series with the electro-magnet winding, and an armature,carried by the said switch and subject to the influence of saidelectro-magnet winding.

In testimony whereof, I have hereunto GEORGE M. LITTLE.

Witnesses: 7

02cm S. SGHAIRER, Bnmnr HINES.

